When ridden with gusto, a stationary bike offers a low-impact way to fit in a quality cardiovascular session. People who are overweight or who have joint problems appreciate its low-impact nature, and riding a stationary bike offers a superb way to cross-train for sports that cause a lot of pounding on the joints. Using a stationary bike for all of your workouts, however, may limit your fitness goals. The machine also can't quite compare to the experience you get riding your bike outdoors.

Calorie Burn

Although the stationary bike is better than sitting on the couch, it doesn't burn as many calories as standing cardiovascular exercises such as jogging or pedaling an elliptical trainer. For example, a 155-pound person burns about 633 calories per hour jogging at a moderate 5.2 mph pace, but the same person only burns 493 calories with an hour of moderate stationary cycling. You have to pedal vigorously to match the calorie burn of a jog.

Limited Impact

When you pedal a bike, your upper body doesn't get a workout. Cycling is also not ideal for improving bone mass. When you are seated on a bike, you aren't bearing your own weight -- this means you are missing out on the muscular work that builds bone density. Augment your stationary cycling workout with a minimum of two total-body strength-training routines weekly to meet the minimum recommendations of exercise for health put forth by the Centers for Disease Control and Prevention.

Monotony

Pedaling a stationary bike can be monotonous, even if you have a book to read or a television to watch. Unlike outdoor exercise, where you can enjoy the landscape and the thrill of new sights and sounds, cycling indoors is quite dull and may encourage you to cut your workout short. Choosing indoor cycling over outdoor exercise also deprives you of some of the mood-boosting benefits of your workout. A meta-analysis of 10 studies published in "Environmental Science and Technology" in May 2010 found that exercising in nature provides a significant improvement in mental health.

Compared to Outdoor Riding

Since you are in control of the resistance and speed, you may be tempted to work at a less-than-vigorous intensity. When you cycle outdoors, you can't avoid hills and wind -- but indoors, you can set the resistance to a low level and pedal away without even breaking a sweat. If you are training for a race, biking indoors doesn't prepare you for the real-life circumstances such as navigating traffic, uneven surfaces and extreme temperatures.

About the Author

Andrea Cespedes is a professionally trained chef who has focused studies in nutrition. With more than 20 years of experience in the fitness industry, she coaches cycling and running and teaches Pilates and yoga. She is an American Council on Exercise-certified personal trainer, RYT-200 and has degrees from Princeton and Columbia University.